HSA is a major protein component of plasma and has been used as a medicine for the treatment of, for example, massive bleeding, shocks, burn, hypoproteinosis, fetal erythroblastosis and so on.
At present, HSA is produced mainly from fractions of collected blood. However, this production method is uneconomical and besides, the supply of the blood from which the HSA is produced is not always assured. Moreover, blood can pose problems since it contains undesirable substances, such as hepatitis virus.
In recent years, production of various useful polypeptides by microorganisms or cells has become possible with the advent of recombinant DNA technology, and studies and developments of large-scale production of HSA by genetic engineering have been made. However, the yield of HSA is low and an industrial production technique which permits HSA production at a low cost with high purity remains to be established.